Computational study on effects of rib height and thickness on heat transfer enhancement in a rib roughened square channel

Abstract

A computational study was carried out for the heat transfer augmentation in a three-dimensional square channel fitted with different types of ribs. The standard k–ε model and its two variants (RNG and realizable) were used for turbulence modeling. The predictions were compared with available experimental and computational results. Three rib configurations were used in the present study: 90° continuous attached ribs, 60° V-shaped broken attached thick and thin ribs. It was observed that the maximum heat transfer occurs at the normalized rib spacing (p/e) = 10 in the case of 90° attached ribs. The effects of the blockage ratio and rib thickness were investigated for 60° V-shaped broken ribs with Re = 10,000–30,000 and p/e = 10. It was observed that the average Nusselt number decreases with an increase in the Reynolds number for almost all configurations studied in the present study. For the 60° V-shaped broken ribs, increasing the blockage ratio had an adverse effect on the heat transfer. It was also observed that thin ribs perform better than thick ribs.